SWEETWATER COUNTY, Wyo. - An imprisoned serial killer has been charged with murder in a 30-year-old cold case out of Sweetwater County, Wyo., authorities confirmed Tuesday.

Rodney James Alcala, 73, of California, convicted of killing seven people, is now being charged with first-degree murder in the death of 28-year-old Christine Ruth Thornton 34 years ago.

During the summer of 1977, authorities believe, Alcala murdered Thornton, of San Antonio, Texas, and dumped her body in a remote area northeast of Granger, a small rural community in western Sweetwater County, according to a press release from Sweetwater County Sheriff’s Office.

Thornton’s remains were not discovered until April 1982 and she was not identified until 2015.

Alcala, commonly known as the “Dating Game Killer” for his appearance on the popular television show, was convicted for the 1979 murder of Robin Samsoe in 1980.

In 2005, the release states, a California grand jury indicted Alcala for the murders of Jill Barcomb, Georgia Wixted, Charlotte Lamb and Jill Parenteau. Alcala was convicted for the women’s murders in 2010 and sentenced to death.

Following his 2010 conviction, the release states, Huntington Beach Police Department Robbery-Homicide Unit released to the public a series of photos Alcala had in his possession in 1979 with the hopes of identifying other potential victims.

The pictures have been posted on the Southern California Public Radio site. Click here to see the photos.

Christine Thornton

The cold case investigation continued in Sweetwater County when detectives submitted a tissue sample of their victim’s remains in 2013 to the University of North Texas Center for Human Identification for mitochondrial DNA analysis and the National Missing and Unidentified Persons System.

The system assists law enforcement agencies to identify missing people through various means, including comparison of DNA samples from unidentified and missing people and relatives of individuals who can submit their own samples for analysis.

Also in 2013, a relative of Thornton’s viewing Alcala’s photos found a picture of the victim, the release indicates. Thornton’s family contacted Huntington Beach police and in 2014 Thornton’s siblings submitted their DNA samples for inclusion in the system.

In July 2015, the release states, Sweetwater County detectives were contacted by the DNA system and alerted to the possible identification of Thornton.

“Detectives were able to determine that the photograph of Thornton in Alcala’s possessions was taken a short distance from where her remains were found,” the release states. “Other evidence discovered during the investigation linked Alcala to Thornton’s homicide.”

Alcala was also convicted in 2012 of two murders from the 1970s that occurred in New York. After given a lengthy prison sentence he was returned to California.

“While Alcala has been deemed a prolific serial killer, authorities don’t know the full extent of his crimes, though they estimate he may have up to 130 victims across the United States,” the release states.

If convicted, Alcala could face death or life in prison in Wyoming.

Anyone who has further information on the case, particularly anyone in contact with Thornton or Alcala during 1977, is encouraged to call Sgt. Joe Tomich at 307-922-5295.